Half of us eat from the air
Industrial ammonia synthesis (Haber–Bosch) now supplies the reactive nitrogen for roughly half of the protein in the global diet.
Plants need reactive nitrogen. For four billion years they depended on lightning and microbes. Haber’s high-pressure catalysis (1909) and Bosch’s industrial scale-up (1913) turned atmospheric N₂ into ammonia on demand.
Vaclav Smil and later analysts estimate that around half of the nitrogen in today’s human protein comes from this process. The Green Revolution’s yields sit on it. So do explosives; the same reaction fed wars and fields.
The bill is environmental: runoff, dead zones, nitrous oxide. The fact remains demographic. A world of eight billion is a world that learned to fix nitrogen with fossil energy. That is not a metaphor.
Caveats
- The ‘half’ figure is an estimate, sensitive to diet and region.
- Organic systems also feed people; they do not feed this many at this density without imported reactive nitrogen from somewhere.
Sources
- 1Smil V.. Enriching the Earth: Fritz Haber, Carl Bosch, and the Transformation of World Food Production. MIT Press, 2001.
- 2Erisman J. W. et al.. How a century of ammonia synthesis changed the world. Nature Geoscience 1, 2008.